I just had a laptop stolen. Even with Time Machine backups, you still spend many hours setting configs after a restore.
But how many hours do you spend establishing, testing, and maintaining a backup plan that mitigates the risk of spending a few hours getting back to working status after a restore?
In my experience, TimeMachine is wonderfully effective at restoring system state (including things like shell customizations, dotfiles, etc). The marginal return on investment in more comprehensive backup setup just doesn't pay dividends. Of course, there's the issue of offsite backups, which typically aren't as comprehensive as TimeMachine.
The point I'm making is that technical folks often have a hard time making value judgements as it relates to technology. Having a backup of your data is 100% necessary. No argument there. Having a backup of your system state? That's not as high a priority, because you're mitigating a future time investment with a current time investment. You have to weigh the two against each other: time spent today versus potentially time spent in the future.
TBH I've moved to Windows as a primary platform now and I'm just using Beyond Compare to sync my data by hand to bitlocker encrypted USB sticks (3x 128Gb Corsair Survivor) and keep one on my keyring, one in the car and one at home. Takes about 2 hours to build a windows machine from scratch now including OS, Office, dev tools, updates onto an SSD. I imagine that would work reasonably well on a Mac too if you skipped half the junk that appeared in the user's profile.
Should you have additional on-site and off-site/cloud backups? Sure. I also use Backblaze as well as having a periodic on-site data files backup. (Plus whatever incidental backup is provided by Flickr and iCloud.) But, from my perspectivem it doesn't hurt to start with a whole disk backup, especially given how easy Time Machine makes it.
I was back up and running within a couple of hours.
There's this process that runs in my head whenever I work on my laptop. (as opposed to working on a coding project) I always keep in mind what the dependencies are, what it would take to replicate this if I lost it.